Unit lock dual dead bolts



P 1969 F. J. RUSSELL ET AL 3,469,876

UNIT LOCK DUAL DEAD BOLTS 2 Sheets-Sheet 1 Filed Feb. 27, 1967 INVENIURS FEED J RUSSELL R/cHaa-o L. ARMS-r2010; Yam/n20 W. JAM/GEES Y 3M4) 411M)- Sept. 1969 F J, RU L ET AL I 3,469,876

UNIT LOCK DUAL DEAD BOLTS Filed Feb. 27, 1967 2 Sheets-Sheet 2 Q?) A HI 2 21 I??? I 6O W I"! l 20 55* sollli 4: es

----'TIITIIEI:L:: wn 49 3;: 1* 68 2e 34 INVENTORS 7 F250 J. Jzusssu.

Vise/V020 Ml SANDEQS BY 5% 5 42M 4 TToPA/E vs United States Patent US. Cl. 292-177 8 Claims ABSTRACT OF THE DISCLOSURE The structure herein disclosed is applicable primarily to a type of lock frequently designated in the trade as a unit type lock. This is a lock which in completely assembled form is applied to a door by inserting it in a cutout extending from the free edge of the door inwardly, the unit type lock being such that it entirely fills the cutout portion of the door with a portion of the lock on opposite sides being flush with opposite faces of the door. In this respect it differs from various other typical lock constructions. The unit type lock herein disclosed is provided with a latch bolt, pivotally mounted inside the end wall of the lock casing, and adapted to be manipulated by a spring-pressed tailpiece. Since unit type locks are customarily built to provide greater security than other conventional type locks, a dead bolt usually is reciprocatably mounted in the case spaced from, but adjacent to the latch bolt, the dead bolt being manipulated by a separate mechanism. In the disclosure here under consideration there is a separate handle for the dead bolt actuating mechanism which, when rotated, operates a spring-biased linkage to extend the dead bolt to locked position, in which position the spring-biased linkage is impelled over center by action of a torsion spring to hold it in locked position. Consequently, as long as this relationship is maintained, the dead bolt cannot be pried out of locked position. At the same time, an extension on the dead bolt falls into position overlying a complementary extension on the latch bolt and the latch bolt is simultaneously anchored in locked position against prospect of being pried to open position.

The invention relates to door locks and, in particular, locks of the type which are identified as unit locks. The subject matter of the invention here under consideration is more particularly directed to a dead locking action, wherein the conventional latch bolt is converted to dead bolt action when a separate dead bolt is extended to locked position, the dead bolt action being one made especially secure.

BACKGROUND OF THE INVENTION Heretofore, in order to construct unit type locks with greater capability of security than other conventional type locks, many manufacturers have restorted to a somewhat complex construction. Moreover, because such locks are customarily installed at locations subject to heavy and frequent use, complex constructions have had their disadvantages.

It is therefore among the objects of the invention to provide a new and improved unit type lock, wherein there is a double dead bolt action, without at the same time ice making the construction any more mechanically involved than one wherein there is but a single dead bolt action.

Another object of the invention is to provide a unit type lock with a double dead bolt action which is simple and positive in its operation and which gives a positive additional degree of security by converting the conventional latch bolt into an additional dead bolt, when the dead bolt is extended to locked position.

Still another object of the invention is to provide a new and improved double dead bolt action which involves the usual dead bolt action, and wherein. the mechanism needed to employ the latch bolt as a dead bolt is so simple that it takes up no room within the lock frame which may be needed for other necessary working parts.

With these and other objects in view, the invention consists in the construction, arrangement, and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims, and illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a side perspective view showing the unit lock as it would be mounted in a door.

FIGURE 2 is a side elevational view partially broken away, showing the latch bolt extended and the dead bolt retracted.

FIGURE 3 is a longitudinal sectional view taken on the line 3-3 of FIGURE 2.

FIGURE 4 is a fragmentary view similar to FIGURE 2, but showing the dead bolt in extended position.

FIGURE 5 is a longitudinal sectional view of the lock with the dead bolt extended and showing the related portion of the door frame.

FIGURE 6 is a longitudinal sectional view taken on the line 6-6 of FIGURE 5.

FIGURE 7 is a cross-sectional view taken on the line 7-7 of FIGURE 5.

DESCRIPTION OF THE CHOSEN EMBODIMENT In the disclosure of the invention which has been selected for purposes of illustration, there is shown a door 10 having an inside face 11, an outside face 12, and a cutout 13 extending inwardly from an edge 14. A unit lock indicated generally by the reference character 15 is housed in a frame consisting of a front end wall 16, side walls 17 and 18, upper and lower end walls like the upper end wall 19, and a rear wall 20. When the unit lock 15 is positioned on the door 10, there is provided a rose 21 and a conventional knob 22 on each side. In FIGURE 5 there is also shown a door frame 23 provided with a typical strike plate 24 in which is a hole 25 for reception of a latch bolt 26 and a dead bolt 27 when in extended or locked position.

In the front end wall 16 is an opening 28 which accommodates the latch bolt 26, adjacent to which is another opening 29 which accommodates the dead bolt 27. The latch bolt 26 is pivotally mounted in the opening 28 by employment of pivot pins 30, one of which is shown in FIGURE 3, and which are pivotally attached in conventional fashion to the front end wall 16. A tailpiece 31 is pivotally attached to the latch bolt 26 by means of a pivot pin 32, at a location spaced from the pivot pin 30, so that when the latch bolt 26 is extended by action of a coil spring 33, acting in, a conventional manner, the latch bolt 26 is extended yieldably to latching position in the hole 25 of the strike plate 24, as

3 viewed in FIGURE 5, movement outwardly of the latch bolt 26 being limited by engagement of a stop pin 34 acting as a shoulder against an inside surface 35 of the front end wall 16, as shown in FIGURES 2, 4, and 6.

The dead bolt 27 is manipulated by a handle 40 which extends through the rose 21 on the inside face 11 of the door 10. Extension and retraction is accomplished by the agency of a spindle 41 nonrotatably attached to the bandle 40. For convenience, the spindle 41 is square and has arms 42 and 43 nonrotatably mounted thereon. Spacers 44 and 45, respectively, may be provided to position the arms 42 and 43 in proper relationship. A link 46 is attached to the arm 42 by means of a pivot pin 47. At its opposite end, the link 46 is pivotally attached to the dead bolt 27 by means of a pivot pin 48. There is a cutout 50 provided at the inside end of the dead bolt 27, in which the pivot pin 48 is located. Similarly, a link 51 is attached at one end by the pivot pin 52 to the arm 43. The same link 51 is pivotally attached to the dead bolt 27 by the pivot pin 48 already described. Spacer 37 may be provided to position links 46 and 51 in proper relationship. A torsion spring 53 has one end 54 in engagement with a portion 55 of a slide 56. The other end 57 of the torsion spring 53 is in engagement with a tab 58 of the link 51. The torsion spring 53 is biased so as to normally hold the linkage comprising the arm 43 and link 51 in the extended position of FIGURES 4 and 6. Since the arm 42 and link 46 occupy accompanying extended positions, they, too, are simultaneously held in extended position by the same torsion spring 53. Additionally, a coiled tension spring 59 has one end 60 in engagement with an annular recess 61 of the spindle 41 and another end 62 in engagement with an annular recess 36 of the spacer 37. Action of the coiled tension spring 59 is normally to withdraw the dead bolt 27 to retracted position, as shown in FIGURES 2 and 3.

To improve the smooth sliding action of the dead bolt 27, there are provided a pair of opposite inwardly fac ing slideways 63 and 64 in the respective side walls 17 and 18, within which outer most edges 65 and 66 are adapted to slidable reciprocate. The slide 56, in turn, is attached to the dead bolt 27 by means of rivets 67.

An extension 68, which is in fact an outwardly bent portion of the slide 56 and because of it a portion of the mechanism moving with the dead bolt 27, is in a position overlying the position of the stop pin 34.

In operation, the latch bolt 26 is normally extended yieldably outwardly by action of the coil spring 33, as previously described. It may be assumed, for convenience in description, that the dead bolt 27 is normally at withdrawn position, as shown in FIGURES 1, 2 and 3. To extend the dead bolt 27 to extended or locked position, as shown in FIGURES 4, 5, and 6, the handle 40 is rotated in a clockwise direction, as viewed in FIGURE 1, simultaneously rotating the spindle 41 in a clockwise direction, as viewed in FIGURES 2, 4, and 6. Movement, as described, rotates the arms 42 and 43 clockwise, and this motion, in turn, shifts the respective links 46 and '51 in a direction generally from right to left, as viewed in FIG- URES 2, 4, and 6, against the tension of the coiled tension spring 59. The result of this is to move the dead bolt 27 in a direction from right to left, as viewed in the same figures, until the dead bolt 27 occupies the position shown in FIGURES 4 and 6. In this position, and due in part to the action of the torsion spring 53, the respective arms 42, 43 and links 46, 51 are moved slightly over center, in which position they are retained by action of the torsion spring 53. For convenience, movement as described may be limited by engagement of stop tab 49 on link 51 against arm 43. It will be noted in the same extended position that the extension 68 lies behind the stop pin 34. Therefore, inasmuch as the over center relationship of the arms 42, 43 and links 46, 51 blocks the dead bolt 27 against retraction by unauthorized means, the same blocking will be communicated to the latch bolt 26, making it impossible to retract the latch bolt 26 by unauthorized means. Should this be attempted, the stop pin 34 will engage the extension 68 and effectively block further motion.

When the dead bolt 27 is to be retracted, it is necessary only to rotate the handle 40 in a counterclockwise direction, as viewed in FIGURE 1. This results in a counterclockwise rotation of the spindle 41, causing the arms 42 and 43 to be rotated counterclockwise and resulting in withdrawing the links 46 and 51 in a direction from left to right, as viewed in FIGURES 2, 4, and 6. Forceable rotation, as described, is suflicient to overcome the torsion spring 53 and, once returned over center, assistance in withdrawing the dead bolt 27 will be provided by the coiled tension spring 59. The same withdrawal of the dead bolt 27 withdraws the extension 68 from its position behind the stop pin 34. Thereafter, the latch bolt 26 can be freely forced inwardly, as it would be by the latch bolt 26 moving against the strike plate 24, in the normal act of closing the door 10.

It will be observed that since the manipulation of the dead bolt 27 is accomplished by nothing more than a pair of arms 42 and 43 and correspondin links 46 and 51 in parallel relationship and since these parts are relatively short, the entire mechanism may be contained in a small chamber 70 within the lock frame 16, 17, 18, 19, 20.

While the invention has herein been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein, but is to be accorded the full scope of the claims, so as to embrace any and all equivalent devices.

Having described the invention, what is claimed as new in support of Letters Patent is:

1. A dead bolt action for a lock comprising a frame having a front wall and side walls extending inwardly from said front wall, said front Wall having a latch bolt aperture and a dead bolt aperture therein, a dead bolt reciprocatably mounted in said dead bolt aperture and a latch bolt including a pivot pivotally mounting said latch bolt on said frame, means for extending said dead bolt to locking position and for returning said dead bolt to unlocking position comprising a spindle rotatably mounted in the frame and having an external handle thereon, drive linkage comprising an arm nonrotatably mounted at one end on said spindle, a link having a single rotatable connection at one end thereof to the other end of said arm, the other end of said link having a rotatable connection to the inside end of said dead bolt, means forming a slideway in said frame and a slide on said dead bolt in sliding engagement with said slideway, whereby to guide movement of said dead bolt between locked and unlocked positions.

2. A dead bolt action as in claim 1, including a tension spring acting between said dead bolt and a stationary point on said frame adapted to assist in withdrawal of said dead bolt.

3. A dead bolt action as in claim 1, including a torsion spring biased between said slide and said linkage and acting in a direction to move said linkage to over center position.

4. A dead bolt action as in claim 1, wherein said drive linkage comprises a pair of spaced, parallel arms nonrotatably mounted on said spindle and a link for each arm in nonrotatable engagement with the dead bolt.

5. A dead bolt action as in claim 4, wherein said tension spring between said arms and wherein there is a torsion spring biased between said slide and said linkage and actin in a direction to move said linkage to over center position.

6. A dead bolt action as in claim 1 including a shoulder on said latch bolt and an extension on said dead bolt overlying said shoulder in extended position of both said bolts,

5 whereby said latch bolt is deadlocked when said dead bolt is extended to locked position.

7. A dead bolt action as in claim 1, wherein said slide way comprises a pair of spaced parallel recesses in said frame and said slide comprises a plate having opposite edges respectively in said recesses.

8. A dead bolt action as in claim 1, including stop means engageable with said linkage having a stop relationship in over center position of said arm and said link when said dead bolt is in extended position.

6 References Cited UNITED STATES PATENTS DAVID J. WILLIAMOWSKY, Primary Examiner J. K. BELL, Assistant Examiner 

